Crossover Controls - JL Audio 450/4V2 Owner's Manual

!
IMPORTANT
The output of the amplifier will decrease for
a given input voltage when the "Input
Range" switch is placed in the "High"
position. Conversely, the output will be
higher with the switch in the "Low" position.
While this may sound counter-intuitive, it is
correct as described.
3) Input Sensitivity Adjustment: Located next
Input Voltage
Input
Sens. Input Voltage
range has been selected, this control can be
used to match the source unit's output voltage
to the input stage of each pair of amplifier
channels for maximum clean output. Rotating
the control clockwise will result in higher
sensitivity (louder for a given input voltage).
Rotating the control counter-clockwise will
result in lower sensitivity (quieter for a given
input voltage). To properly set each pair
of amplifier channels for maximum clean
output, please refer to Appendix B (page 22)
in this manual. After using this procedure,
you can then adjust the relative level of each
channel pair by adjusting the input sensitivity
downward on either or both channel pairs, if
they require attenuation to achieve the desired
Input
Sens.
beyond the maximum level established during
the procedure outlined in Appendix B (page
and possible speaker damage. Be aware that
Input Sens.
made, regardless of how many input cables are
feeding the amplifier. These controls will allow
you to set the appropriate relative levels for CH
1&2 relative to CH 3&4 and other amplifier
channels in the system.
8 | JL Audio - 450/4 Owner's Manual
v2

CROSSOVER CONTROLS

Crossovers are groups of individual electronic
filters which allow only certain frequency
ranges to pass through them by attenuating
frequencies outside the selected range. These
filters allow the user to specify what frequency
range will be sent out of each channel section
of the amplifier. This, in turn, allows each
speaker system to only reproduce a range of
frequencies it is well-suited for, resulting in
reduced distortion and improved fidelity.
CH 1&2 Filter Section:
trol CH 1 & 2 Filter Section
Freq. Range Filter Mode | Slope
c Filter Input V
0Hz x1 | x10 Off | 12dB | 24dB Low |
95
r Filter Type
75 130
e
he
nput 60 200
to
hen
LP | BP | HP
50 500
ed.
CH
Filter Freq. (Hz)
(Le
1) Filter Type
CH 1&2 Filter Section
you to configure the CH 1&2 filter into one
of three filter types:
LP Low-Pass): Configures the CH 1&2
filter to attenuate frequencies above
the selected filter frequency. Useful
for connection of subwoofer(s) to CH
1&2 in a bi-amplified system.
BP
attenuate frequencies above the selected filter
frequency and below the frequency selected
in the CH 3&4 High-Pass Filter. This creates
a true bandpass filter well-suited for driving
mid-bass or mid-range speakers in a tri-
amplified system.
HP High-Pass): Configures the CH 1&2
filter to attenuate frequencies below the
selected filter frequency. Useful for connection
of component speakers to CH 1&2 in a bi-
amplified system.
2) Filter Mode/Slope
allows you to defeat the CH 1&2 filter or select
from two filter slopes.
Off
allowing the full range of frequencies present
at the inputs to feed that pair of channels.
crossovers or requiring full-range reproduction
from that pair of channels.
12dB
to attenuate frequencies above or below the
selected filter frequency at a rate of 12 dB per
octave (Butterworth alignment).
24dB
to attenuate frequencies above or below the
selected filter frequency at a rate of 24 dB per
the vehicle, different filter slopes may be
required to produce a smooth transition
between the sound of different speakers in the
system. Experiment to find the slope which
best matches the acoustic requirements of
24dB
do a better job of protecting small speakers
with limited power handling. The shallower
12dB
to reproduce more low-frequency content.
3) Freq. Rang
the right, this switch multiplies the cutoff
Filter Freq.
(Hz) x1
position, the range of the rotary control is
x10
position, the range of the rotary control is
4) Filter Freq. (Hz)
markings surrounding this rotary control
are for reference purposes and are generally
accurate to within 1/3 octave or better. If you
would like to select the filter cutoff frequency
with a higher level of precision, consult the
charts in Appendix A (page 22) of this manual.
CH 3&4 Filter Section:
CH 3 & 4 Filter Section CH 3
Freq. Range High-Pass Filter Inpu
x1 | x10 Off | 12dB | 24dB Low
95
Mode Also sets
75 130
low-pass
cutoff for
60 200
CH 1 & 2
Bandpass
| 4ch Filter
50 500
(if selected)
1 & 2
and HP Filter Freq. (Hz)
(
3 & 4
1) High-Pass Filter
you to defeat the CH 3&4 filter or select from
two different filter slopes.
Off
allowing the full range of frequencies present
at the inputs to feed that pair of channels.
crossovers or requiring full-range reproduction
from these channels.
12dB
3&4 to attenuate frequencies below the selected
filter frequency at a rate of 12 dB per octave
(Butterworth alignment).
24dB
3&4 to attenuate frequencies below the selected
filter frequency at a rate of 24 dB per octave
vehicle, different filter slopes may be required to
produce a smooth transition between the speakers
in the system. Experiment to find the slope
which best matches the acoustic requirements
24dB
will do a better job of protecting small speakers
with limited power handling. The shallower
12dB
reproduce more low-frequency content.
2) Freq. Range
right, this switch multiplies the cutoff frequency
Filter Freq. (Hz)
x1
x10
9